Chemistry Commons^™

Titanium Dioxide Sensitized With Porphyrin Dye As A Photocatalyst For The Degradation Of Water Pollutants, Kevin Reyes, Ivana Jovanovic

Publications and Research

TiO2 was sensitized with a porphyrin, Tetra(4-carboxyphenyl) porphyrin(TCPP) and used as photocatalyst under visible light for degradation of aqueous solutions of methylene blue (MB) dye. The quantification of the degradation of MB was assessed by UV-Vis spectroscopy. The results of this procedure showed the decrease in concentration of MB over time when reaction is exposed to visible light. The TiO2-TCPP complex was tested as well for the recovery of metals from the AgNO3 aqueous solution. The reduction of silver cations to silver metal was observed through formation of black precipitate.

Visible Light-Triggered Carbon Monoxide-Releasing Molecules, Marina Popova

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Carbon monoxide (CO) is now well established as one of the signaling molecules in higher organisms, including humans. Due to its physiological roles, CO is now accepted as a potential therapeutic agent. The use of CO gas has been studied in multiple clinical trials. Vasodilation, anti-inflammatory, anti-apoptotic, anti-proliferative and cytoprotective effects are just a few of the pharmacological actions attributed to CO gas in various models of diseases. Use of inhaled CO gas as a therapeutic has many limitations which necessitate the development of a new approach for CO delivery. In order to handle CO safely, compounds that release CO …

Bridging The Molecular/Material Divide: An Investigation Into The Properties Of Polyesters, Terra Marie M. Jouaneh

Senior Honors Projects

By definition, polymers consist of large molecules composed of small, repeating units called monomers. These monomers give characteristic material properties to polymers, whether they be the melting point, the folding character, or the inherent stability. Many of the objects we encounter on a daily basis are composed of polymers. These polymers may be synthetic, such as the plastic in disposable bags, or natural, like glycogen in the liver. Recent developments in biotechnology have used synthetic polymers in drug delivery, contact lenses, and even organ transplants. Polyesters, in particular, have been utilized pharmacologically due to their biodegradable properties. Understandably, not all …

Nanomaterials-Based Electrodes For Lithium-Ion Batteries And Alcohol Fuel Cells, Lakshman K. Ventrapragada

All Dissertations

This dissertation describes my research on surfactant-free synthesis of nanomaterials with applications for alcohol fuel-cell electrodes, and design and fabrication of nanomaterials-based current collectors that improve the performance of lithium-ion batteries (LIBs) by replacing existing current collectors.

Chapter 1 provides a background on the electroanalytical tools used in this research, and an introduction to fuel cells and LIBs.

Chapter 2 describes a novel synthesis method for fabricating gold-graphene composites by laser ablation of a gold strip in water. A well-known limitation in the fabrication of a metal-graphene composite is the use of surfactants that strongly adsorb on the metal surface …

Molecular Machines: Synthesis, Modeling, And Applications, Syd Kotar

Student Scholar Symposium Abstracts and Posters

While some of the smallest, most useful machines known to science are the biological molecules that keep living organisms alive, there is a growing advancement of the creation of artificial molecules that have the same function and are more efficient. Molecular machines were invented in 1983 when scientists in France created a machine formed of two interlinked molecular rings. In 2016, the Nobel prize in chemistry was awarded to Feringa, Stoddart, and Sauvage who finally documented molecular machines and put them into energy‐filled states in which their movements could be controlled. From this, molecular machines became known as a group …

Preparation And Characterization Of Ruthenium-Gold Raman-Active Catalytic Surfaces, Thang Nguyen

Student Scholar Symposium Abstracts and Posters

Heterogeneous reactions at the gas-solid interface play a major role in many important industrial and environmental processes. These reactions typically rely on metal surfaces, to act as a catalyst between gas phase reactants and products. The catalysts lower the transition state barrier in the formation of the products. The mechanisms of reactions on catalysts is often not fully known due to the difficulty of observing the bond breakage and formation between gaseous molecules at the interface. One method in which the catalytic mechanism can be studied is by using Raman Spectroscopy. However, one drawback of this method is the fact …

An Investigation Of Alkylboron Transmetallation In Palladium-Catalyzed Suzuki Reactions, Benjamin Murray

Dissertations, Theses, and Capstone Projects

Through the past 40 years, carbon-carbon cross-coupling reactions have greatly enhanced the ability of chemists to synthesize C(sp²)-C(sp²) bonds and more recently C(sp²)-C(sp³) bonds. In particular, the Suzuki reaction has proven to be invaluable with its high yields, good functional group tolerance, and low toxicity of reagents. One of the component steps of the catalytic cycle of this reaction is transmetallation, in which the nucleophilic species transfers its organic component to the metal center (generally palladium). The mechanism of transfer from primary alkylboron nucleophiles was studied in the 1990's via use of …

A Pretargeted Spect Imaging Strategy Employing Technetium-99m Based On Bioorthogonal Diels-Alder Click Chemistry, Justin H. Walsh

Dissertations, Theses, and Capstone Projects

A series of related N₃S ^99mTc-peptide complexes were synthesized and tested for use in pretargeting SPECT imaging that utilizes the bioorthogonal Diels-Alder click reaction between tetrazine (Tz) and transcyclooctene (TCO). The objective was to optimize the excretory pathways of the ^99mTc-peptide complexes for maximum tumor targeting with the in vivo “click” and minimum non-target uptake. The ^99mTc–tetrazine constructs were prepared by reaction of ^99mTc-peptide complexes (^99mTc-FKC, ^99mTc-FKCR, ^99mTc-DKC, and ^99mTc-SKC) with Tz-NHS or Tz-PEG₅-NHS to form ^99mTc FK(Tz)C, ^99mTc-FK(PEG₅-Tz)CR, ^99mTc-DK(PEG₅-Tz)C, …

Spontaneous Advent Of Genetic Diversity In Rna Populations Through Multiple Recombination Mechanisms, Benedict A. Smail, Bryce E. Clifton, Ryo Mizuuchi, Niles Lehman

Chemistry Faculty Publications and Presentations

There are several plausible abiotic synthetic routes from prebiotic chemical materials to ribonucleotides and even short RNA oligomers. However, for refinement of the RNA World hypothesis to help explain the origins of life on the Earth, there needs to be a manner by which such oligomers can increase their length and expand their sequence diversity. Oligomers longer than at least 10-20 nucleotides would be needed for raw material for subsequent natural selection. Here, we explore spontaneous RNA-RNA recombination as a facile means by which such length and diversity enhancement could have been realized. Motivated by the discovery that RNA oligomers …

Crystal Structures Of Dotma Chelates From Ce³+ To Yb³+ : Evidence For A Continuum Of Metal Ion Hydration States, Mark Woods, Katherine M. Payne, Edward J. Valente, Benjamin E. Kucera, Victor G. Young

Chemistry Faculty Publications and Presentations

The crystal structures of chelates formed between each stable paramagnetic lanthanide ion and DOTMA are described. A total of 23 individual chelates structures were obtained, in each chelate the coordination geometry around the metal ion is best described as a twisted square antiprism (torsion angle -25.0° – - 31.4°). Despite the uniformity of the general coordination geometry provided by the DOTMA ligand, there is a considerable variation in the hydration state of each chelate. The early Ln3⁺ chelates are associated with a single inner sphere water molecule, the Ln-OH₂ interaction is remarkable for being very long. After a …

In Situ Nmr Parameter Monitoring Systems And Methods For Measuring Ph And Temperature, Ming Huang, Lingyu Chi, Rex E. Gerald Ii, Jie Huang, Annalise R. Pfaff, Klaus Woelk

Electrical and Computer Engineering Faculty Research & Creative Works

Devices and methods are provided for measuring temperatures and pHs of a sample in situ using NMR spectroscopy, and for sealing one or more ends of a capillary tube after a reference material has been added to the capillary tube, which is used in an in situ NMR temperature measurement device. A method for measuring a pH of a sample in situ using NMR spectroscopy includes providing an in situ NMR pH measurement device. This device includes a sample housing member configured to house a target sample, at least one pH sensor configured to exhibit an NMR spectral change due …

Kinetic Study Of Silver Nanoparticle Formation, Steven A. Diaz

Ursidae: The Undergraduate Research Journal at the University of Northern Colorado

With the increased use of silver nanoparticles in modern day applications, kinetic information on the mechanism of their formation is useful for further studies on its reactivity in a biological environment. Silver nanoparticles were synthesized using a modified Turkevich method. The synthesized nanoparticles were characterized using UV-Visible spectroscopy. The data obtained were plotted as a function of time, and rate constants for the nucleation (k₁) and autocatalytic surface growth (k₂) were extracted. Comparing the k₁ (~10^-3) and k₂ (~10^-1) values supports a two-step mechanism of slow nucleation and fast autocatalytic …

Influence Of Monomer Deformation On The Competition Between Two Types Of Σ-Holes In Tetrel Bonds, Rafal Wysokiński, Mariusz Michalczyk, Wiktor Zierkiewicz, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

One of several tetrel (T) atoms was covalently attached to three F atoms and a substituted phenyl ring. A NH3 base can form a tetrel bond with TF3C6H2R3(T = Si, Ge, Sn, Pb; R = H, F, CH3) in a position opposite either an F atom or the ring. The σ-hole opposite the highly electron-withdrawing F (T-F) is more intense than that opposite the ring (T-C). However, when the Lewis base deforms from a tetrahedral to a trigonal bipyramidal shape so as to accommodate the base, it is the T-C σ-hole that is more intense. Accordingly, it is the T-C …

Red-Shifting Mutation Of Light-Driven Sodium-Pump Rhodopsin, Keiichi Inoue, María Del Carmen Marín, Sahoko Tomida, Ryoko Nakamura, Yuta Nakajima, Massimo Olivucci, Hideki Kandori

Chemistry Faculty Publications

Microbial rhodopsins are photoreceptive membrane proteins that transport various ions using light energy. While they are widely used in optogenetics to optically control neuronal activity, rhodopsins that function with longer-wavelength light are highly demanded because of their low phototoxicity and high tissue penetration. Here, we achieve a 40-nm red-shift in the absorption wavelength of a sodium-pump rhodopsin (KR2) by altering dipole moment of residues around the retinal chromophore (KR2 P219T/S254A) without impairing its ion-transport activity. Structural differences in the chromophore of the red-shifted protein from that of the wildtype are observed by Fourier transform infrared spectroscopy. QM/MM models generated with …

Multiple Local Σ-Aromaticity Of Nonagermanide Clusters, Nikolay V. Tkachenko, Alexander I. Boldyrev

Chemistry and Biochemistry Faculty Publications

Nonagermanide clusters are widely used in inorganic synthesis and are actively studied by experimentalists and theoreticians. However, chemical bonding of such versatile species is still not completely understood. In our work we deciphered a bonding pattern for various experimentally obtained nonagermanide species. We localized the electron density via the AdNDP algorithm for the model structures ([Ge₉]⁴⁻, [Ge₉{P(NH₂)₂}₃]⁻, Cu[Ge₉{P(NH₂)₂}₃] and Cu(NHC)[Ge₉{P(NH₂)₂}₃]) and obtained a simple and chemically intuitive bonding pattern which …

Generalizing Metallocene Mechanochemistry To Ruthenocene Mechanophores, Ye Sha, Yudi Zhang, Enhua Xu, C Wayne Mcalister, Tianyu Zhu, Stephen L. Craig, Chuanbing Tang

Faculty Publications

Recent reports have shown that ferrocene displays an unexpected combination of force-free stability and mechanochemical activity, as it acts as the preferred site of chain scission along the backbone of highly extended polymer chains. This observation raises the tantalizing question as to whether similar mechanochemical activity might be present in other metallocenes, and, if so, what features of metallocenes dictate their relative ability to act as mechanophores. In this work, we elucidate polymerization methodologies towards main-chain ruthenocene-based polymers and explore the mechanochemistry of ruthenocene. We find that ruthenocene, in analogy to ferrocene, acts as a highly selective site of main …

Synthesis And Application Of A Magnetic Nanoparticle Based Nano-Complex For Targeted Cell Death In Glioblastoma Multiforme Cells, Matthew Tovar

Departmental Honors & Graduate Capstone Projects

In the last ten years, there has been little advancement in the treatment of the aggressive brain cancer Glioblastoma Multiforme (GBM). This work describes the synthesis of a superparamagnetic iron oxide (SPION)-based nanotheraputic complex for use in targeting and killing aggressive mesenchymal GBM cells. The average sizes (and therefore magnetic properties) of the synthesized SPIONs are precisely tailored via a novel time-controlled approach utilizing a previously described electrochemical reaction. Through this synthetic method, the optimal particle size (OPS) where maximal thermal energy is released upon stimulation with an external magnetic field was determined to be 21 nm. The nano-complex was …

Surface-Enhanced Infrared Absorption Spectroscopy- Surface Sensitive In Situ Label-Free Spectroelectrochemistry, Lie Wu, Jian-Long Sun, Xiu-E Jiang

Journal of Electrochemistry

Surface-enhanced infrared absorption spectroscopy (SEIRAS), especially in attenuated total reflectance (ATR) mode, taking advantages of surface-enhancement and near-field optical effect of enhancing substrate, is a ultra-sensitive infrared spectroscopy, which could achieve surface-selected detection at a sub-monolayer level. Since the enhancing substrate could simultaneously serve as a working electrode, ATR-SEIRAS is a readily surface-sensitive in situ label-free spectroelectrochemistry technique. With the advantages of small influence from metal species on enhancement effect, good potential reversibility of spectra, simple surface selection rule and sensitivity to polar molecules, ATR-SEIRAS has been widely applied in the fields of orientation analysis and species identification of interfacial …

High-Efficiency Nitrite Sensor Based On Cop Nanowire Array, Fu-Ling Zhou, Xiao-Li Xiong, Xu-Ping Sun

Journal of Electrochemistry

Nitrite has a negative impact on the environment and human health. The long-term consumption of nitrite-containing foods has a carcinogenic risk. Therefore, the analysis and detection of nitrite are important. It is of great significance to develop high-efficiency electrocatalysts to achieve high sensitivity and selectivity for nitrite detection. The cobalt phosphide nano-array (CoP/TM) was obtained by hydrothermal and low-temperature phosphating. The electrochemical test results show that the constructed CoP/TM was a highly efficient electrochemical reduction nitrite catalyst with the excellent sensing performance and response time less than 3 s, as well as the linear detection range of 1.0 μmol·L^{-1 …}

Analysis Of Western African Textiles Through Analytical Methods, Kathryn L. Dodds

Undergraduate Distinction Papers

A technical art analysis of select objects (88.04, 73.02, 70.07, and 86.01) from the Western African collection at the Frank Museum of Art at Otterbein University (Westerville, Ohio) was executed. Since little is known about the materials used in the Western African collection, the characterization of the surface may help better understand the historical aspects and origins of the objects. In order to identify pigments, binding materials, and dyes on the object’s surface a multi-pronged approach was implemented, including x-ray fluorescence (XRF), X-ray diffraction (XRD), widefield fluorescence microscopy (WFM), liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS). Object 88.04 …

Low Molecular Weight Fluorescent Probes (Lmfps) To Detect The Group 12 Metal Triad, Ashley D. Johnson, Rose M. Curtis, Karl J. Wallace

Faculty Publications

Fluorescence sensing, of d-block elements such as Cu²⁺, Fe³⁺, Fe²⁺, Cd²⁺, Hg²⁺, and Zn²⁺ has significantly increased since the beginning of the 21st century. These particular metal ions play essential roles in biological, industrial, and environmental applications, therefore, there has been a drive to measure, detect, and remediate these metal ions. We have chosen to highlight the low molecular weight fluorescent probes (LMFPs) that undergo an optical response upon coordination with the group 12 triad (Zn²⁺, Cd²⁺, and Hg²⁺), as these metals have …

In Situ/Operando Visualization Of Electrode Processes In Lithium-Sulfur Batteries: A Review, Shuang-Yan Lang, Xin-Cheng Hu, Rui Wen, Li-Jun Wan

Journal of Electrochemistry

Lithium-sulfur (Li-S) batteries have been regarded as one of the most promising candidates for the next-generation energy storage devices. Fundamental understanding of the structure and evolution processes at electrode-electrolyte interfaces is essential to the further development. In this review, we summarize recent advances in the interfacial observations by means of various in situ/operando visualization techniques, including scanning probe microscopy (SPM), electron microscopy (EM), X-ray microscopy (XRM) and optical microscopy (OM). The real-time investigation provides important evidence for the morphology and component changes including S/Li₂S transformation, polysulfide dissolution on cathodes and Li/solid electrolyte interphase (SEI) evolution on anodes, which …

Sensitive And Reusable Electrogenerated Chemiluminescence Aptasensor Fabricated By Electrochemically Double Covalent Coupling Method For The Detection Of Cocaine, Xiao-Feia Wang, Tinga Zhang, Bing Wang, Hong-Lan Qi, Cheng-Xiao Zhang

Journal of Electrochemistry

A double covalent coupling method based on click chemistry and diazonium chemistry was developed for the fabrication of a sensitive and reusable electrogenerated chemiluminescence (ECL) aptasensor. As a proof-of-concept, cocaine was chosen as a model target, and a specific aptamer was chosen as a recognition molecule element, while ruthenium complex derivative (Ru1) as an ECL signal compound. The ECL aptasensor was fabricated by electrochemically diazotizing a phenylazide on the surface of a glassy carbon electrode, and then, coupling the alkyne functionalized Ru1-labeled cocaine aptamer through click chemistry. The ECL aptasensor was facilely used to determine cocaine in the range from …

A Facile Strategy For Two-Step Fabrication Of Gold Nanoelectrode For In Vivo Dopamine Detection, Li-Hao Guan, Chao Wang, Wang Zhang, Yu-Lu Cai, Kai Li, Yu-Qing Lin

Journal of Electrochemistry

In vivo monitoring neurochemicals with microelectrode is invasive and the damage to brain tissue may inevitably cause disturbance signals physiologically to the measurement. It is of great importance to reduce the electrode size and to decrease the damage. This study demonstrates a novel nanoelectrode preparation methodology for in vivo monitoring dopamine (DA) fluctuation in the living brain of rats with high dependability. The fabrication process of the gold nanoelectrode involving a few minutes consists of only two steps: 1) growing gold nanoseeds on surface of tip of glassy capillary by ion sputtering; 2) wet depositing a continuous conductive gold film …

Preparation And Electrocatalytic Oxygen Reduction Performance Of Self-Doped Sludge-Derived Carbon, Ya-Li Ye, Wei-Ming Feng, Ge Li, Zhen-Chao Lei, Chun-Hua Feng

Journal of Electrochemistry

The development of low-cost, high-performance cathode catalysts is critical for practical application of fuel cells. Here, the N, P-doped porous graphene-like carbon with outstanding oxygen reduction reaction (ORR) performance was synthesized by pyrolysis of surplus sludge, which functioned as a self-doped, self-activated, and self-templated precursor by acclimation with continuous feedings of phenol. The results show that the amounts of microorganisms were enriched after acclimation, with increasing contents of N, P, Fe, as well as C atoms. The increasing pyrolysis temperature resulted in the formation of an ordered graphitic structure, however, the excessively high temperature induced the drop in the amounts …

Electrochemical Analysis And Sensing Preface, Yi-Tao Long, Yang Tian

Journal of Electrochemistry

No abstract provided.

Advanced Electrochemical Strategy For In Vivo Detection Of Electrochemically Inactive Molecules, Qi Zhou, Li-Min Zhang, Yang Tian

Journal of Electrochemistry

Development of efficient electrochemical strategies for in vivo analysis of electrochemically inactive molecules in brain is significant for understanding and studying their molecular mechanism and roles playing in brain and brain diseases. This review gives a brief introduction on the advanced in vivo electrochemical sensor for detection of non-redox active molecules from three aspects: 1) The selection and design of specific molecules are highly desirable to develop electrochemical sensors with high selectivity for measuring electrochemical inactive molecules through converting specific chemical reaction involved by target to electric signal; 2) The analysis based on ion current rectification occurred at spatial confined …

Recent Progress Of Electrochemiluminescence Sensors Based On Electrically Heated Electrode, Hui-Fang Zhang, Yi-Ting Chen, Fang Luo, Zhen-Yu Lin, Guo-Nan Chen

Journal of Electrochemistry

Electrochemiluminescence (ECL) has broad application in the fields of environmental monitoring and biological analysis due to its intrinsic advantages such as excellent versatility, good detection sensitivity, and high specificity. The intensity of ECL can be influenced by temperature variation in the ECL quantum efficiency and the rate of electrochemical reaction. However, traditional temperature control is commonly realized through bulk solutions heating, which is complicated and unfavorable for detection when the volatile and thermally unstable materials existed. In order to address these problems, electrically heated electrodes are used to adjust the temperature desired. The major character of this technique lies in …

Application Of Nanomaterials In The Detection Of Volatile Organic Compounds In Exhaled Breath For Cancer Diagnosis, Wan-Qiao Bai, Xue-Zhi Qiao, Tie Wang

Journal of Electrochemistry

Volatile organic compounds (VOCs) generated in human body can reflect one’s health state, and numerous diseases are identified by some VOCs biomarkers. More recently, analyses of VOCs biomarkers from exhaled breath have turned into a research frontier worldwide because it offers a noninvasive way for diseases diagnosis. Various kinds of nanomaterials are used to enhance the performance of sensing techniques, and play an essential role in miniaturization detection. In this review, several kinds of nanomaterials (metallic, metal oxide, carbon-based, composites and MOFs-based materials) used in various VOCs detection methods, especially in VOCs sensors are summarized. Learning from the successful utilization …

Sensitive Photoelectrochemical Assay Of Nucleic Acids Based On Catalytic Hairpin Assembly And Ru(Nh3)63+, Ya-Min Fu, Xiao-Xia Yan, Xiao-Hua Zhang, Jin-Hua Chen

Journal of Electrochemistry

A simple “signal-on” photoelectrochemical (PEC) sensing platform for sensitive assay of nucleic acids was developed by coupling catalytic hairpin assembly (CHA) signal amplification strategy with Ru(NH₃)₆³⁺. Herein, cadmium sulfide (CdS) was deposited on the TiO₂/indium tin oxide (ITO) electrode by a method of successive ionic layer adsorption and reaction (SILAR), serving as one kind of photoelectric material to broaden absorption range of TiO₂ and to improve the photoelectric conversion efficiency. Thereafter, the capture DNA (C-DNA) was immobilized on the CdS/TiO₂/ITO electrode. Simultaneously, Au-hairpin DNA probe 1 (Au-HP1) and hairpin DNA …